Biodiversity is the variation in living organisms, viewed within a given habitat, ecosystem or in the world as a whole. The concept is usually applied to the species diversity, although the notion of genetic biodiversity is applied to the variation in genes within an individual species. While most people think of rainforests as loci of great biodiversity, biomes such as oceans and grasslands are the likely repositories for even greater variation. Retention of diverse biota is important, since intact ecosystems are thought to be essential for provision of ecosystem services to humans, including maintenance of a diverse foodbank, pollination, clean water, flood control, pest control, waste decomposition, biomass energy resources and climate stability. Biodiversity is presently critical since we live in the era of the Mass Holocene Extinction, a period of species loss caused by man, and unrivaled in rate of species loss. Although the number of total species numbers in the tens of millions, most have not yet even been described. The extinction of a species is almost always related to destruction of habitat or man-made pollution.
The Spinner dolphin (Stenella longirostris), a marine mammal in the family of oceanic dolphins, engages in formation of small schools. This cetacean species evinces a dominance...
Sierra Madre Oriental pine-oak forestsLast Updated on 2013-12-12 21:20:37
The Sierra Madre Oriental pine-oak forests contains a very diverse community of endemic and specialized species of plants, mammals, reptiles and amphibians. This ecoregion is classified as an element of the Tropical and Subtropical Coniferous Forests biome. These high mountains run north to south, beginning in the USA and ending in Mexico. The Sierra Madre Oriental pine-oak forests are a highly disjunctive ecoregion, owing to the fact that they are present only at higher elevations, within a region with considerable expanses of lower elevation desert floor.
The variation accumulated in this distance, between its ends and elevation ranges, increases the diversity of habitats and species present. For example, habitats in the north, near Big Bend, Texas are arid or desert-like with the influences of the Chihuahuan Desert; in the south, rainfall increases greatly, creating... More »
Sierra Madre Occidental pine-oak forestsLast Updated on 2013-12-12 15:19:32
The Sierra Madre Occidental pine-oak forests ecoregion boasts some of the richest biodiversity anywhere in North America, and contains about two thirds of the standing timber in Mexico. Twenty-three different species of pine and about 200 species of oak reside within the Sierra Madre Occidental pine-oak forests ecoregion. Many distinctive species have evolved here as a result of the landforms, altitude, temperature and rainfall. However, over-harvesting of the forests in this area since the early part of this century has caused the extinction of the imperial woodpecker (the largest woodpecker on Earth) and has lead to the likelihood of several other species becoming extinct in this ecoregion, such as the Mexican gray wolf. Currently, all but 300,000 acres, or about two percent, of the original old-growth forest is gone.
This ecoregion occurs disjunctively along the Sierra Madre... More »
Arizona Mountains forestsLast Updated on 2013-12-10 10:46:49
The Arizona Mountain Forests extend from the Kaibab Plateau in northern Arizona to south of the Mogollon Plateau into portions of southwestern Mexico and eastern Arizona. This ecoregion is an element of the Temperate Coniferous Forests biome. The species richness in this ecoregion is moderate, with vertebrate taxa numbering 375 species. The topography consists chiefly of steep foothills and mountains, but includes some deeply dissected high plateaus. Elevations range from 1370 to 3000 meters (m) with some peaks as high as 3840 m. Soil types have not been well defined; however, most soils are entisols, with alfisols and inceptisols in upland areas. Stony terrain and rock outcrops occupy large areas on the mountains and foothills.
Vegetation zones in this ecoregion resemble the Rocky Mountain Life Zones but at higher elevations. Although forests in this ecoregion are too far south to... More »
Chihuahuan DesertLast Updated on 2013-12-06 23:07:07The Chihuahuan Desert encompasses one of the most biologically diverse arid regions on Earth. This ecoregion extends from within the United States south into Mexico. This desert is unique, as it has been sheltered from the influence of other arid regions such as the Sonoran Desert by the large mountain ranges of the Sierra Madres. This isolation has allowed the evolution of many endemic species; most notable is the high number of endemic plants; in fact, there are a total of 653 vertebrate taxa recorded in the Chihuahuan Desert. Moreover, this ecoregion also sustains some of the last extant populations of Mexican Prairie Dog, wild American Bison and Pronghorn Antelope.
Severe conservation pressures are on the Chihuahuan Desert. On the Mexico side, there are destructive activities from illegal poaching, habitat destruction from illegal drug trafficking and large scale movements of... More »
California coastal sage and chaparralLast Updated on 2013-12-05 20:18:34
The California coastal sage and chaparral ecoregion, located along the southern and central coast of California, has extremely high levels of species diversity and endemism. The coastal sage scrub is an endangered ecosystem that contains a number of endangered species. The California Gnatcatcher is currently being used as an umbrella species to protect the endemic flora and fauna of this region from urban development. The region is listed as an Endemic Bird Area with a large number of endemic scrub species. Generally located on high value coastal zone real estate and threatened by land development, the ecoregion represents the struggle between ecological preservation and human development.
The California coastal sage and chaparral encompasses coastal terraces, plains, and foothills along the Pacific coast of northwestern Mexico and southern California, USA. The Santa Rosa Mountains... More »
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